DESCRIPTION: (Adapted from applicant's abstract.) The evaluation of optical quality of the normal and abnormal cornea has been limited principally to measurements of visual performance such as contrast sensitivity, acuity and glare. While these measures reflect aspects of corneal optical quality, they do not readily reflect changes in optical performance as a function of pupil size, nor give insight to the specific cause of the various optical improvements or deficits. The specific aim of this research is to develop fast, objective measures of corneal optical quality, capable of predicting changes in visual performance for any pupil size of interest. This will be accomplished by calculating the monochromatic wave aberrations of the cornea from the state-of-the-art corneal topography measurements on normal eyes and patients having various corneal conditions which disrupt normal corneal topography. These data will in turn be used to quantify the amount and degree of variation in the higher order aberrations and their influence on the optical transfer function (OTF) of the cornea for normal eyes and eyes with disrupted corneal topography; and predict the resulting changes in the eye's visual performance as a function of pupil size. The ultimate goal of the research is to identify the relationship between altered corneal topography and diminished visual function, thus lessening the adverse consequences of corneal therapies designed to improve the image quality of the eye.